Background: RABEX-5, a guanine nucleotide exchange factor (GEF) for RAB-5, plays an important role in cell mobility and altered expression associated with tumor metastasis. This study aimed to investigate the role of RABEX-5 in proliferation and metastasis of breast cancer in vitro and ex vivo. Methods. RABEX-5 expression was examined in breast cancer, benign tumor and normal breast tissues by immunohistochemistry and western blot. Two stable cell lines were established, the MCF-7/NC negative control cell line and the MCF-7/KD cell line, which stably expressed an RNA interference (RNAi) construct that induced downregulation of RABEX-5 expression. These cell lines were utilized to evaluate the role of RABEX-5 in cell proliferation and migration in vitro and tumorigenicity in vivo. The possible role of RABEX-5 in the regulation of matrix metallopeptidase 9 (MMP-9) was evaluated using western blot and real-time PCR. Results: RABEX-5 expression was found to be significantly higher in breast cancer tissues compared with benign tumor and normal breast tissues. High levels of RABEX-5 expression were associated with axillary lymph node metastasis. In addition, RABEX-5 silencing significantly reduced cancer cell proliferation, colony formation and migration ability in vitro and inhibited tumor growth in vivo. RABEX -5 knockdown also attenuated the migration of breast cancer cells via modulation of MMP-9 transcriptional activity. Conclusions: Our results indicate that RABEX-5 plays an oncogenic role in breast cancer by modulating the proliferation and metastasis potential of breast cancer cells. Thus, RABEX-5 is a promising prognostic indicator for patients with breast cancer. © 2013 Zhang et al.; licensee BioMed Central Ltd.
CITATION STYLE
Zhang, X., Min, J., Wang, Y., Li, Y., Li, H., Liu, Q., … Li, H. (2013). RABEX-5 plays an oncogenic role in breast cancer by activating MMP-9 pathway. Journal of Experimental and Clinical Cancer Research, 32(1). https://doi.org/10.1186/1756-9966-32-52
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